Monsoon rains likely to spread over UP; west coast rainfall subsides

New Delhi, Friday June 23 The monsoon remained stationery in the last twenty four hours and the Northern Limit of Monsoon (NLM) continues to pass through Veraval, Navasari, Malegaon, Betul, Jabalpur, Siddhi, Varanasi and Gorakhpur. The northern limit of monsoon is an imaginary line that connects places where the monsoon has reached at a given point in time.

Meanwhile, a trough has developed from Uttarakhand to north Bay of Bengal cutting through east Uttar Pradesh, Bihar, Jharkhand and Gangetic West Bengal, at mean sea level. The trough formation will lead to enhanced rainfall activity over the regions where it is journeying through.

The trough is expected to funnel monsoon further inside Uttar Pradesh along the Gangetic plains. Heavy showers are also a chance at one or two places in these parts.
Troughs are places where winds from opposing directions meet (or winds turn) and atmospheric pressure is low while the turbulence caused by such interaction (or turning) leads to rain, thundershowers and storms.

A cyclonic circulation over Gangetic West Bengal and neighborhood still persists. The weather system would usher in light rainfall over West Bengal, Jharkhand, Chhattisgarh, east Madhya Pradesh and Orissa.

The offshore west coast trough is enfeebling and extends from Goa to Kerala. The weak trough would subdue rainfall activities along the west coast. Mumbai rains have also turned light and isolated after an initial excess after monsoon’s arrival.

An east-west shear zone (wind gradient over relatively shorter distances) extends roughly along the seventeen degree north latitude. This would enhance rainfall activity over Rayalseema, Telangana, north interior Karnataka and the adjoining areas.

A Western Disturbance is on its way and is Afghanistan. The weather system is expected to move east northeastwards towards India and reach by June 24. But the Western Disturbance will pass through the higher latitudes and is likely to cause only light showers over Jammu & Kashmir.

But the Western Disturbance spells bad news for the northwest plains as the preceding warm front will push mercury levels even further.
Western Disturbances are westerly (traveling west to east) weather systems that originate due to evaporation over the Mediterranean or the Caspian Seas.
A cyclonic circulation over south Pakistan and adjoining west Rajasthan has merged with the heat low over northwest plains. The situation does not proclaim any relief from the prevailing heat wave conditions.